Establishment of nasal tolerance to heat shock protein-60 alleviates atherosclerosis by inducing TGF-β-dependent regulatory T cells

Vaccination as a Promising Approach in Cardiovascular Risk Mitigation: Are We Ready to Embrace a Vaccine Strategy?

Cardiovascular disease (CVD) remains a leading global health concern, with atherosclerosis being its principal cause. Standard CVD treatments primarily focus on mitigating cardiovascular (CV) risk factors through lifestyle changes and cholesterol-lowering therapies. As atherosclerosis is marked by chronic arterial inflammation, the innate and adaptive immune systems play vital roles in its progression, either exacerbating or alleviating disease development. This intricate interplay positions the immune system as a compelling therapeutic target. Consequently, immunomodulatory strategies have gained increasing attention, though none have yet reached widespread clinical adoption. Safety concerns, particularly the suppression of host immune defenses, remain a significant barrier to the clinical application of anti-inflammatory therapies. Recent decades have revealed the significant role of adaptive immune responses to plaque-associated autoantigens in atherogenesis, opening new perspectives for targeted immunological interventions. Preclinical models indicate that vaccines targeting specific atherosclerosis-related autoantigens can slow disease progression while preserving systemic immune function. In this context, numerous experimental studies have advanced the understanding of vaccine development by exploring diverse targeting pathways. Key strategies include passive immunization using naturally occurring immunoglobulin G (IgG) antibodies and active immunization targeting low-density lipoprotein cholesterol (LDL-C) and apolipoproteins, such as apolipoprotein B100 (ApoB100) and apolipoprotein CIII (ApoCIII). Other approaches involve vaccine formulations aimed at proteins that regulate lipoprotein metabolism, including proprotein convertase subtilisin/kexin type 9 (PCSK9), cholesteryl ester transfer protein (CETP), and angiopoietin-like protein 3 (ANGPTL3). Furthermore, the literature highlights the potential for developing non-lipid-related vaccines, with key targets including heat shock proteins (HSPs), interleukins (ILs), angiotensin III (Ang III), and a disintegrin and metalloproteinase with thrombospondin motifs 7 (ADAMTS-7). However, translating these promising findings into safe and effective clinical therapies presents substantial challenges. This review provides a critical evaluation of current anti-atherosclerotic vaccination strategies, examines their proposed mechanisms of action, and discusses key challenges that need to be overcome to enable clinical translation.

Two decades of vaccine development against atherosclerosis

Atherosclerosis is an immune-mediated chronic inflammatory disease that leads to the development of fatty plaques in the arterial walls, ultimately increasing the risk of thrombosis, stroke, and myocardial infarction. The immune response in this complex disease is both atheroprotective and pro-atherogenic, involving both innate and adaptive immunity. Current treatments include the adjustment of lifestyle factors, cholesterol-lowering drugs such as statins, and immunotherapy, whereas vaccine development has received comparatively little attention. In this review, we discuss the potential of antigen-specific vaccination as a preventative approach based on more than 20 years of research and innovation. Vaccination targets include proteins that are more abundant in atherosclerotic patients, such as oxidized low-density lipoprotein (LDL), apolipoprotein B-100, proprotein convertase subtilisin/kexin type-9 serine protease (PCSK9), cholesteryl ester transfer protein (CETP), and heat shock proteins HSP60 and HSP65. Immunization with such proteins or their peptide epitopes has been shown to induce T-cell activation, produce antigen-specific antibodies, reduce the size of atherosclerotic lesions, and/or reduce serum cholesterol levels. Vaccination against atherosclerosis therefore offers a new strategy to address the burden on healthcare systems caused by cardiovascular disease, the leading cause of death worldwide.

Autoimmunity: A New Focus on Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) has long been considered a benign, chronic inflammatory, and hyperplastic disease. Recent studies have shown that autoimmune-related mechanisms are involved in the pathology of nasal polyps. Activated plasma cells, eosinophils, basophils, innate type 2 lymphocytes, mast cells, and proinflammatory cytokine in polyp tissue indicate the mobilization of innate and adaptive immune pathways during polyp formation. The discovery of a series of autoantibodies further supports the autoimmune nature of nasal polyps. Local homeostasis dysregulation, infection, and chronic inflammation may trigger autoimmunity through several mechanisms, including autoantigens overproduction, microbial translocation, molecular mimicry, superantigens, activation or inhibition of receptors, bystander activation, dysregulation of Toll-Like Receptors (TLRs), epitope spreading, autoantigens complementarity. In this paper, we elaborated on the microbiome-mediated mechanism, abnormal host immunity, and genetic changes to update the role of autoimmunity in the pathogenesis of chronic rhinosinusitis with nasal polyps.

Bridging nanoplatform and vaccine delivery, a landscape of strategy to enhance nasal immunity

Vaccination is an urgently needed and effective option to address epidemic, cancers, allergies, and other diseases. Nasal administration of vaccines offers many benefits over needle-based injection including high compliance and less risk of infection. Inactivated or attenuated vaccines as convention vaccine present potential risks of pathogenic virulence reversal, the focus of nasal vaccine development has shifted to the use of next-generation (subunit and nucleic acid) vaccines. However, subunit and nucleic acid vaccine intranasally have numerous challenges in development and utilization due to mucociliary clearance, mucosal epithelial tight junction, and enzyme/pH degradation. Nanoplatforms as ideal delivery systems, with the ability to enhance the retention, penetration, and uptake of nasal mucosa, shows great potential in improving immunogenic efficacy of nasal vaccine. This review provides an overview of delivery strategies for overcoming nasal barrier, including mucosal adhesion, mucus penetration, targeting of antigen presenting cells (APCs), enhancement of paracellular transportation. We discuss methods of enhancing antigen immunogenicity by nanoplatforms as immune-modulators or multi-antigen co-delivery. Meanwhile, we describe the application status and development prospect of nanoplatforms for nasal vaccine administration. Development of nanoplatforms for vaccine delivery via nasal route will facilitate large-scale and faster global vaccination, helping to address the threat of epidemics.

GARP and GARP-Treated tDC Prevented the Formation of Atherosclerotic Plaques in ApoE-/- Mice

Purpose

This study aims to clarify the specific mechanism by which GARP affects the atherosclerotic plaques in ApoE^−/- mice and the effect of GARP-tDC on atherosclerosis.

Methods

The mice were randomly divided into three groups: the control group, the GARP-overexpressed group and the GARP-inhibited group. After 12 weeks, all the mice were euthanized, and the specimens were collected. In vitro, experiments were conducted to observe the effect of GARP on DC phenotype and the changes of the proportion of CD4⁺CD25⁺Foxp3⁺ Treg cells when GARP-tDCs were co-cultured with CD4⁺ T cells. Furthermore, adoptive transmission of GARP-tDCs was used to observe the effect on atherosclerotic plaque in mice.

Results

The GARP-overexpressed group enhanced the biological activity of Foxp3⁺ CD4⁺CD25⁺ Tregs and resulted in increased expression of LAP in T cells. In addition, the GARP-overexpressed group significantly suppressed the function of Th1 and Th17, and decreased the secretion of INF-γ and IL-17A. Thus, GARP had a protective effect on atherosclerosis. In vitro, we found that GARP-tDC had a tolerance-inducing phenotype, and GARP-tDC also had the ability to induce tolerance when co-cultured with CD4⁺ T cells. More importantly, adoptive transmission of GARP-tDCs reduced the size of atherosclerotic plaques.

Conclusion

GARP and the GARP-tDC play protective roles in atherosclerosis. The protective effect of GARP on atherosclerosis is achieved by increasing CD4⁺CD25⁺Foxp3⁺ Treg cells and inhibiting the production of IFN-γ and IL-17A.

Heat shock protein 60 and cardiovascular diseases: An intricate love-hate story

Cardiovascular diseases (CVDs) are the result of complex pathophysiological processes in the tissues comprising the heart and blood vessels. Inflammation is the main culprit for the development of cardiovascular dysfunction, and it may be traced to cellular stress events including apoptosis, oxidative and shear stress, and cellular and humoral immune responses, all of which impair the system's structure and function. An intracellular chaperone, heat shock protein 60 (HSP60) is an intriguing example of a protein that may both be an ally and a foe for cardiovascular homeostasis; on one hand providing protection against cellular injury, and on the other triggering damaging responses through innate and adaptive immunity. In this review we will discuss the functions of HSP60 and its effects on cells and the immune system regulation, only to later address its implications in the development and progression of CVD. Lastly, we summarize the outcome of various studies targeting HSP60 as a potential therapeutic strategy for cardiovascular and other diseases.

Hsp60 and IL-8 axis promotes apoptosis resistance in cancer

Background

Interleukin-8 (IL-8) and heat shock protein 60 (Hsp60) play crucial roles in cell survival and maintenance of cellular homoeostasis. However, cross talks between these two proteins are not defined.

Methods

IL-8 expression in tumour tissue sections was analysed by immunohistochemistry. IL-8 expression and release in cancer cells was quantified using enzyme-linked immunosorbent assay (ELISA). Apoptosis was quantified using caspase activity and Annexin-V/PI staining.

Results

We observed IL-8 release from cancer cells in response to histone deacetylase inhibitor, apicidin (Api), and non-competitive inhibitor of the sarco/endoplasmic reticulum Ca²⁺ ATPase, thapsigargin (TG). IL-8 release was increased upon TG-treatment. TG-induced IL-8 expression was reduced in the presence of Api in Bax-dependent manner. Increased apoptosis was associated with decreased IL-8 expression in response to combined treatment of TG and Api. TG and Api combination induced caspase-8 and caspase-9 dependent apoptosis. Hsp60 knockdown abrogated IL-8 expression induced by Api, TG, and their combination. The level of TGF-β, an upstream regulator of IL-8, was decreased upon Hsp60-silencing. Knocking down Hsp60 decreased IL-8 expression and its release in prostate cancer cell xenograft tumours in SCID mice.

Conclusion

This study describes the underlying mechanism associated with apoptosis resistance mediated via Hsp60-IL-8 axis in cancer.

Atherosclerosis and autoimmunity: a growing relationship

Atherosclerosis is regarded as one of the leading causes of mortality and morbidity in the world. Nowadays, it seems that atherosclerosis cannot be defined merely through the Framingham traditional risk factors and that autoimmunity settings exert a remarkable role in its mechanobiology. Individuals with autoimmune disorders show enhanced occurrence of cardiovascular complications and subclinical atherosclerosis. The mechanisms underlying the atherosclerosis in disorders like rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid syndrome, systemic sclerosis and Sjögren's syndrome, seem to be the classical risk factors. However, chronic inflammatory processes and abnormal immune function may also be involved in atherosclerosis development. Autoantigens, autoantibodies, infectious agents and pro-inflammatory mediators exert a role in that process. Being armed with the mechanisms underlying autoimmunity in the etiopathogenesis of atherosclerosis in rheumatic autoimmune disorders and the shared etiologic pathway may result in substantial developing therapeutics for these patients.

Current prospects and future challenges for nasal vaccine delivery

Nasal delivery offers many benefits over traditional approaches to vaccine administration. These include ease of administration without needles that reduces issues associated with needlestick injuries and disposal. Additionally, this route offers easy access to a key part of the immune system that can stimulate other mucosal sites throughout the body. Increased acceptance of nasal vaccine products in both adults and children has led to a burgeoning pipeline of nasal delivery technology. Key challenges and opportunities for the future will include translating in vivo data to clinical outcomes. Particular focus should be brought to designing delivery strategies that take into account the broad range of diseases, populations and healthcare delivery settings that stand to benefit from this unique mucosal route.

Tolerization against atherosclerosis using heat shock protein 60

Atherosclerosis is a chronic inflammatory disease of the artery wall, and both innate and adaptive immunity play important roles in the pathogenesis of this disease. In several experimental and human experiments of early atherosclerotic lesions, it has been shown that the first pathogenic event in atherogenesis is intimal infiltration of T cells at predilection sites. These T cells react to heat shock protein 60 (HSP60), which is a ubiquitous self-antigen expressed on the surface of endothelial cells (ECs) together with adhesion molecules in response to classical risk factors for atherosclerosis. When HSP60 is expressed on the EC surface, it can act as a "danger-signal" for both cellular and humoral immune reactions. Acquired by infection or vaccination, beneficial protective immunity to microbial HSP60 and bona fide autoimmunity to biochemically altered autologous HSP60 is present in all humans. Thus, the development of atherosclerosis during aging is paid by the price for lifelong protective preexisting anti-HSP60 immunity by harmful (auto)immune cross-reactive attack on arterial ECs maltreated by atherosclerosis risk factors. This is supported by experiments, which shows that bacterial HSP60 immunization can lead and accelerate experimental atherosclerosis. This review article presents accumulating proof that supports the idea that tolerization with antigenic HSP60 protein or its peptides may arrest or even prevent atherosclerosis by increased production of regulatory T cells and/or anti-inflammatory cytokines. Recent data indicates that HSP60, or more likely some of its derivative peptides, has immunoregulatory functions. Therefore, these peptides may have important potential for being used as diagnostic agents or therapeutic targets.

Intranasal immunization with heat shock protein 60 induces CD4(+) CD25(+) GARP(+) and type 1 regulatory T cells and inhibits early atherosclerosis

Atherosclerosis is an autoimmune inflammatory disease involving both innate and adaptive immune mechanisms. Immune tolerance induction may have therapeutic potential for the suppression of atherosclerosis. Current interest is directed towards mucosal tolerance induction, especially nasal tolerance. Previous studies have shown that heat shock protein 60 (HSP60) is recognized as an important autoantigen in atherosclerosis, and nasal or oral HSP60 can induce tolerance and ameliorate atherosclerosis by inducing several subsets of regulatory T cells (Tregs ) such as latency-associated peptide (LAP)(+) and forkhead box transcription factor 3 (FoxP3)(+) Tregs. However, little is known regarding the detailed mechanisms of nasal tolerance. Here, we again investigated the impact of nasal HSP60 on atherosclerosis and the mechanisms underlying the anti-atherosclerosis responses. We found that nasal HSP60 caused a significant 33·6% reduction in plaque size at the aortic root in the early stages of atherosclerosis (P < 0·001). Notably, a significant increase in activated CD4(+) CD25(+) glycoprotein A repetitions predominant (GARP)(+) Tregs, type 1 Tregs (Tr1 cells), and CD4(+) CD25(+) FoxP3(+) Tregs, as well as a marked decrease in the numbers of type 1 and 17 T helper cells was detected in the spleens and cervical lymph nodes of HSP60-treated mice. Moreover, nasal HSP60 increases the production of transforming growth factor (TGF)-β and interleukin (IL)-10 and decreases the secretion of IFN-γ and IL-17. Interestingly, the atheroprotective role of nasal HSP60 treatment was abrogated partly by the neutralization of IL-10. Our findings show that nasal administration of HSP60 can attenuate atherosclerotic formation by inducing GARP(+) Tregs, Tr1 cells and FoxP3(+) Tregs, and that these Tregs maintain immune homeostasis by secreting IL-10 and TGF-β.

The role of heat shock proteins in atherosclerosis

Atherosclerosis is a chronic, multifactorial disease that starts in youth, manifests clinically later in life, and can lead to myocardial infarction, stroke, claudication, and death. Although inflammatory processes have long been known to be involved in atherogenesis, interest in this subject has grown in the past 30-40 years. Animal experiments and human analyses of early atherosclerotic lesions have shown that the first pathogenic event in atherogenesis is the intimal infiltration of T cells at arterial branching points. These T cells recognize heat shock protein (HSP)60, which is expressed together with adhesion molecules by endothelial cells in response to classic risk factors for atherosclerosis. Although these HSP60-reactive T cells initiate atherosclerosis, antibodies to HSP60 accelerate and perpetuate the disease. All healthy humans develop cellular and humoral immunity against microbial HSP60 by infection or vaccination. Given that prokaryotic (bacterial) and eukaryotic (for instance, human) HSP60 display substantial sequence homology, atherosclerosis might be the price we pay for this protective immunity, if risk factors stress the vascular endothelial cells beyond physiological conditions.

Heat shock proteins and regulatory T cells

Heat shock proteins (HSPs) are important molecules required for ideal protein function. Extensive research on the functional properties of HSPs indicates that HSPs may be implicated in a wide range of physiological functions including immune function. In the immune system, HSPs are involved in cell proliferation, differentiation, cytokine release, and apoptosis. Therefore, the ability of the immune system, in particular immune cells, to function optimally and in unison with other physiological systems is in part dependent on signaling transduction processes, including bidirectional communication with HSPs. Regulatory T cells (Tregs) are important T cells with suppressive functions and impairments in their function have been associated with a number of autoimmune disorders. The purpose of this paper is to examine the relationship between HSPs and Tregs. The interrelationship between cells and proteins may be important in cellular functions necessary for cell survival and expansion during diseased state.

Treg-mediated suppression of atherosclerosis requires MYD88 signaling in DCs

TLR activation on CD11c+ DCs triggers DC maturation, which is critical for T cell activation. Given the expansion of CD11c+ DCs during the progression of atherosclerosis and the key role of T cell activation in atherogenesis, we sought to understand the role of TLR signaling in CD11c+ DCs in atherosclerosis. To this end, we used a mouse model in which a key TLR adaptor involved in DC maturation, MYD88, is deleted in CD11c+ DCs. We transplanted bone marrow containing Myd88-deficient CD11c+ DCs into Western diet-fed LDL receptor knockout mice and found that the transplanted mice had decreased activation of effector T cells in the periphery as well as decreased infiltration of both effector T cells and Tregs in atherosclerotic lesions. Surprisingly, the net effect was an increase in atherosclerotic lesion size due to an increase in the content of myeloid-derived inflammatory cells. The mechanism involves increased lesional monocyte recruitment associated with loss of Treg-mediated suppression of MCP-1. Thus, the dominant effect of MYD88 signaling in CD11c+ DCs in the setting of atherosclerosis is to promote the development of atheroprotective Tregs. In the absence of MYD88 signaling in CD11c+ DCs, the loss of this protective Treg response trumps the loss of proatherogenic T effector cell activation.